This invention relates to decorative glass which, though patterned to simulate mortared glass block, is temperable. This invention further relates to methods of making such articles as well as tempered patterned glass products made therefrom.
Patterned glass and techniques for making such glass have generally been known for over a century. Examples of such known patterned glass and techniques for making them may be found in the following patents:
U.S. Pat. Nos.
21,896
34,843
370,176
370,178
720,138
720,139
737,707
1,528,194
3,183,140
5,622,019.
As can be seen from certain of these prior art patents, such as U.S. Pat. Nos. ""176; ""178; ""194; and much more recently ""019 (all employing generally similar techniques), one or more rollers are employed to imprint within either (or both) of the top or bottom planar surface of the glass a desired pattern, e.g. to simulate stacked glass blocks. For example, in the ""019 patent (see FIG. 2 of the ""019 patent) dual rollers (top/bottom) impress between them a softened sheet of-glass thereby imprinting in the glass a block-like grid with a wavy pattern therebetween. Few operating parameters are given and temperability is not disclosed.
In another example, the ""176 patent employs a smooth top roller when impressing a ridge pattern into the lower planar surface of the glass sheet that has been placed on an appropriately grooved table. This patent also discloses the prior use of a grooved top roller and a smooth casting table on which the glass sheet resides. No operating parameters or depth of grooves or height of sheet ridges is given.
In yet another example, the above-listed ""178 patent teaches to achieve a ridged pattern and a wavy-like pattern with dual, top rollers, one of which has formed in it the ridge pattern to be impressed in the sheet, while the other is provided with a wavy pattern impressed in the blocks outlined by the ridges. Once again no operating parameters or depth of roller grooves or height of sheet ridges or wavy pattern penetration is given. The underside surface of the sheet is maintained smooth by employing a smooth table top beneath the rollers. In the ""194 patent, as a still further example, a top roller with grid patterned ribs is employed to impress a series of grooves into the top of a softened glass sheet, thus forming a grid pattern of grooves which seek to simulate glass blocks (or tiles).
As can be seen from the above, one known technique seeks to simulate a grid by ridges, while another does so with grooves. Each is desirous of creating a grid-like appearance, but none, except the ""019 patent, establishes a depth of groove or height of ridge for doing so. None, moreover, teach the ability to temper, or how to temper such a patterned array. This noticeable absence of any reference to the ability to temper marks a significant, commercially inhibiting problem in the prior art, and demonstrates the unique improvement achieved by this invention. In this respect, the more modern ""019 patent does teach that its grooves are to extend to a depth of xc2xc inch into the planar surface of the glass. This simply serves to highlight the commercially inhibited nature of block simulating sheet glass heretofore known in the art. Because of the intolerance of glass. having high angular dimensional changes in its surface structure, to tempering, this depth of xc2xc inch virtually assures that the sheet is not temperable in that it will likely fail (break in unacceptably large numbers) either during tempering or later in use even if and in the unlikely event that, it survives the tempering process.
Tempered glass in modern architecture is not just a desirable product. It may also be mandatory to use in certain instances, particularly when various safety codes or common sense seek to protect against the severe lacerations that can occur from the breaking of untempered glass. Thus, for example, the use of the more expensive tempered form of decorative windows, glass shower stall doors, or sheets of glass used as interior walls is often required or economically justifiable, thereby creating a significant need in the art for a reliably temperable patterned glass sheet which may be used by itself or in aesthetically matchable form with its tempered counterpart.
The problem when seeking to manufacture a commercially acceptable simulated glass block pattern, temperable or not, is actually twofold. First, one must achieve temperability to satisfy the need in the marketplace (e.g. for safety) as above-described. Second, a consistent and aesthetically pleasing simulating pattern at least approaching the appearance of a true stack of glass blocks separated by mortar must be achieved. Due to the nature of tempering and its intolerance to abrupt changes in surface direction, it has been found that these two requirements, i.e. appearance vs. temperability are in conflict, and one cannot be achieved without eliminating the other.
It is rather apparent from the above that there exists a need in the art for an aesthetic, simulated, reliably temperable glass block patterned sheet of glass, as well as a method of making same, which meets the various architectural and safety needs in the wall, door and window art as above-described. It is a purpose of this invention to fulfill this and other needs in the art which will become more apparent to the skilled artisan once given the following disclosure.
It is a finding of this invention that if the grooves or ridges (and any other pattern if used therewith and also impressed into the surface of a glass sheet) are carefully constructed so as to fall within a certain, heretofore unrecognized and rather precise range of dimensions as to their maximum depth or height below or above, respectively, the plane defined by the planar surface of the glass sheet in which they are formed, the patterned sheet so formed may be both tempered and yet, to the naked eye, present an aesthetically pleasing and acceptably simulating appearance of a plurality of stacked glass blocks.
In certain preferred embodiments, by properly forming the grooves or ridges to an appropriate width and creating in their lateral upper (outer) planar surfaces a granular pattern, two enhancing effects are achieved without negating temperability. First, the granular appearance and its resulting diffusion of light serve to highlight (i.e. better offset, optically) the block-like nature of the overall grid pattern formed. Second, the granular nature of the pattern, appropriately accomplished, simulates the mortar (adhesive) normally employed to form the joints between blocks when constructing a wall from real glass blocks, thereby bringing the appearance of the wall more in line with a real glass block wall or window or door, and away from the artificial simulation that, in fact, it is.
It has been found, in this respect, that for most glasses contemplated, principally clear or colored glass of conventional window glass composition (e.g. a conventional or known soda-lime-silica glass), that if the ridges are maintained at a height less than, or the grooves to a depth less than, about 0.03 inches, and preferably less than 0.016 inches (e.g. 0.0156 inches) with respect to the basic planar surface of the glass sheet, both temperability and an aesthetically pleasing glass block appearance results. The same dimensional limits hold true, in this respect, for any wavy pattern in the block surface itself or in forming a mortar-like granular pattern in the grid region (as described more fully below). In this respect, ridges are preferred rather than grooves. In either event, by adhering to these dimensional limits it has been found that the patterned sheets so formed not only achieve the appearance intended but are quite tolerant of the tempering process, resulting in high yields (low breakage losses) during tempering and create no undue risk of spontaneous failure in normal use when tempered, over their anticipated lifetime, yet are truly tempered as that term is understood in the glass art.